Last week, EPA released its second external review draft of an updated Policy Assessment on the national ambient air quality standard for ozone. It also released updated draft risk and exposure assessments. To no one’s surprise, the new drafts confirm support for lowering the ozone NAAQS from 75 ppb to a range of 60 ppb to 70 ppb.

Why is this not a surprise? Because, as I noted some time ago, the prior draft policy assessment also supported a NAAQS in the range of 60 ppb to 70 ppb. Moreover, the Clean Air Science Advisory Committee weighed in on the prior draft, supporting a standard in the 60 ppb to 70 ppb range. In fact, before getting cold feet, CASAC had indicated that the data would support a standard below 60 ppb.

Courts’ deference to CASAC determinations on these issues is pretty well established. It seems clear that EPA has to lower the NAAQS to at most 70 ppb in order to survive judicial review. It’s not even obvious that 70 ppb would stick, though that will be clearer after CASAC has reviewed this most recent draft Policy Assessment.

The other significant question is when EPA will actually issue the new standard. After all, EPA was prepared to issue a new standard in 2011 or early 2012, when the White House put the proverbial kibosh on EPA’s plans. Will EPA somehow manage to delay issuance of the new standard until after the November elections? Now that the Super Bowl is over, I think that the Vegas bookies are putting their money on after.

EPA has proposed lowering the NAAQS to a range of from 0.060 ppm – 0.070 ppm. Earlier this week, EPA’s Clean Air Science Advisory Committee, or CASAC, met and endorsed EPA’s proposed range. Some CASAC members did express concern about EPA’s proposed secondary seasonal standard, intended to protect crops and forests. However, overall, the CASAC seal of approval is pretty much the end of this argument.

It is important to recall how we got here. CASAC already endorsed the 0.060 ppm – 0.070 range several years ago, before EPA’s last ozone standard was issued. It was EPA’s refusal to follow the CASAC recommendations, and instead propose a 0.075 ppm standard, which led to litigation challenging the standard and the current controversy.

Thus, a standard that does not comport with CASAC’s recommendations would likely be rejected by the courts as arbitrary and capricious. However, I suspect that CASAC’s influence also runs the other way. Assuming that EPA does indeed promulgate a revised NAAQS in the 0.060 ppm – 0.070 ppm range, and assuming that industrial interests challenge the new standard, it will be very difficult to establish that the new standard is arbitrary and capricious if it has been endorsed by CASAC.

As I noted in connection with the fine particulate standard, it’s not obvious to me that this is a good thing. Depending on whose ox is being gored, anyone can get up on a soapbox and say that they want science to be free of politics. However, these are really policy decisions. It’s one thing to acknowledge that these are complicated issues and we thus have to allow Congress to delegate its authority to the EPA administrator. It’s another effectively to delegate the decision further to the CASAC, which is about as obscure an acronym body as we have. Do we really want standards which will result in compliance costs in at least the tens of billions of dollars being made by groups which truly are not accountable in any meaningful way?

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